Effect of soil-structure interaction on seismic earth pressure acting on building basements using 1g shaking table tests

Abstract

The design of seismic earth pressures acting on basement walls has been conducted without taking soil–structure interactions (SSIs), especially the influence of the superstructure, into careful consideration. Accordingly, this study performed a series of 1 g shaking table tests to investigate the effect of SSI on the seismic pressure acting on basement walls. Three types of models—0-story, 3-story, and 9-story—that all contained the same three-story basement were used. The experimental models were organized into two groups: one simulating an embedded basement and the other simulating a basement fixed to bedrock. Three sinusoidal waves with different acceleration amplitudes were used as input motions. The tests evaluated the soil–basement displacement relationship, distribution and magnitude of seismic earth pressure, and the phase relationship between seismic thrust and building displacement, considering different building heights, input acceleration amplitudes, and basement fixity. The seismic earth pressure on basement walls varied with the soil–basement displacement relationship, increasing or decreasing from the initial static earth pressure depending on the relative displacement magnitudes. As the building height increased, the distribution of seismic earth pressure changed from triangular to inverted triangular, and the magnitude of seismic thrust increased by six times for embedded basements and about two times for fixed basements. The seismic earth pressure acted as a resisting force in low-rise buildings and as a driving force in the 9-story building. In the fixed basement cases, the trend was reversed, with seismic earth pressure acting as a driving force in the low-rise buildings and as a resisting force in the 9-story.